SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2534cf67f19c9eecafba5c8871fc29363e567148ad934a663c88cd707c99cee8' 
  AND token = 'DSeVYhXFuoaITuP82rHnqcIxGZOlZpo+1L1+zjdVghc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}